What are you starting with? Do you already have a photo that you want to convert? Are you taking a photo with a digital camera. Are you scanning a photo? If you have a photo and if you have windows paint and can get the photo open in paint you can "save as" and click GIF. If you want to do an animated Gif then you'll have to do something else. Most cameras will convert in camera. As will most scanners.

There are websites which provides the user to create animated images. I am explaining you about how to make animated pictures. Just log in to the site , upload your photo , in page you will see lot of options from there you can choose your choice of your own. IF your question is how to convert JPEG to gif format, its simple just open the image with mspaint and then save as .gif,